1. Field
This invention relates to means for ventilating and aspirating the respiratory tracts of medical patients. It is particularly directed to an improved ventilation circuit interface system, catheter assembly and suction valve.
2. State of the Art
Interface systems for endotracheal suctioning and ventilating virtually all include a manifold structure enabling introduction of ventilating gases and intermittent exhalation of patient breath simultaneously with insertion and option of a tracheal suctioning catheter. These interface systems generally also include some means for selectively communicating a vacuum source the suctioning catheter. Almost universally, these systems involve at least one collapsible, plastic envelope entirely surrounding the catheter and purporting to provide a sterile barrier between the otherwise exposed external surface of the catheter and the ambient atmosphere. In practice, a practitioner manually externally collapses the envelope onto the external surface of the catheter and advances the catheter into the trachea of a patient, retracting the catheter in a similar fashion following the aspiration procedure.
These close-system devices under present medical protocol are ordinarily used at least hourly for up to 48 hours for each patient before being replaced. Problems attendant to such frequent and repeated in-dwelling use are numerous, including, among other problems, constriction of the catheter lumen and valve flow path with undesired respiratory secretions, some of which thicken with age, creation of contaminant-passing pinholes in the collapsible plastic barrier and the need to physically move the lengthy and cumbersome devices from one location on the body of the patient to another when the devices interfere with other procedures. Associated with the dried and drying secretions inside the lumen, are like secretions on the exterior of the catheter wall which accumulate at the manifold wiper seal. Such thick and undesired respiratory secretions not only restrict the facile movement of the catheter through the manifold, but also can be unavoidably reintroduced to the patient in subsequent repeat procedures.
Structures and methods descriptive of the current state of the art are described, among other places, in U.S. Pat. Nos. 5,333,606 to Schneider et al.; U.S. Pat. No. 5,025,806 to Palmer et al.; U.S. Pat. No. 4,850,350 to Jackson; U.S. Pat. No. 4,588,160 to Flynn et al.; U.S. Pat. No. 4,453,295 to Laszczower; and U.S. Pat. No. 4,351,328 to Bodai.
The foregoing patents collectively disclose methods and apparatus for performing endotracheal suctioning procedures on a medical patient without the need for disconnecting the patient from a respirator. During such procedures, positive end expiratory pressure is maintained without interruption during suctioning and with notable ease of catheter removal from an associated ventilation manifold. These patents include description of structures for selectively constricting the fluid flow path within the catheter lumen by manual compression of a tube clamping device.
There remains a need for a ventilating and aspirating device, wherein a single-patient, single-use suction catheter may be releasably coupled at its distal (patient) end to a single-patient, multiple-use manifold and may be releasably coupled at its proximal (user) end with a multiple-patient, multiple-use valve.
Also, a need remains for a tracheal suctioning device which accommodates alternative means of protecting a user from exposure to contamination from the external surface of the suctioning catheter.
A further need remains for a reusable valve structure which can be selectively locked in a closed position yet be readily mechanically actuated between an open position and a closed position without exertion of ongoing manual pressure to maintain the valve in either position.